Purpose: The purpose of this study was to identify the relationship among cognitive style, creative action, and challenging work and then determine whether challenging work has a mediating effect between cognitive style and creative action. Methods: Data were collected from a convenience sample of 275 clinical nurses who graduated from 3-year nursing schools and worked in hospitals in Seoul or Kyungki Province. The questionnaire included measurements of cognitive style, creative action and challenging work. Data were analyzed using descriptive statistics, correlation, T-test, ANOVA, Duncan test, and hierarchical multiple regression. Results: Mean scores for cognitive style, creative style, and challenging work were $3.28{pm}0.42$, $3.22{pm}0.57$, $3.40{pm}0.63$, respectively. Significant correlations were found between cognitive style and challenging work, cognitive style and creative action, and challenging work and creative action. Cognitive style was significantly different according to years in clinical career, and in hospital size. Challenging work was significantly different according to age and position. Creative action was significantly different according to years in clinical career. Finally challenging work had a mediating effect between cognitive style and creative action. Conclusion: Findings from this study provide a comprehensive understanding of challenging work for clinical nurses and indicate related factors and importance.